Pressure compensator



July 5, 1938. w. c. WAGNER 2,122,597

PRESSURE COMPENSATOR Filed July 6, 1.935 5 Shee'ts-Sheet 1 .umu

INVENTOR. Mlfez* Lfzglzw; 133%* AT ORNEY.

July 5, 1938. w. c. WAGNER PRESSURE -COMPENSATOR Filed July 6, 1935 sheets-Sheet v2 INVENTOR. Lidy/ze July 5, 1938. w. C. WAGNER 2,122,597

u PRESSURE COMP-ENSATOR Y Filed July 6,' 1935 5 sheetssheet 3 IN VEN TOR.

BY l @$51.4 Gwq ATTO EY.

July 5, 1938. wl c. WAGNER PRESSURE COMPENSATOR Filed July e, 1935 5 sheets-sheet 5 Afm/PMiX Patented July 5, 1938 UNITED STATES PATENT OFFICE PRESSURE comENsA'roa Walter C. Wagner, Ardmore, Pa. Application July s, 1935, scriol No. 30,209

s calms. (ol. 'za- 233) This invention relates to metering of ilow of section on the line 2-2 of Fig. 3, of the device gases and vapors, and, in particular, relates to of Figure 1.

a pressure compensator. Figure 3 is a section on the line 8-3 of Figure Heretofore, pressure compensators to be used 2, with parts omitted for the sake of clarity. in conjunction with gaseous or vapor flow meters, Figure 4 is a fragmentary section on the line 5 to permit direct registration in units of weight 4--4 of Figure 3. or in units of volume at a standard pressure, re- Figure 5 is a side elevational view, partly in quired highly complicated mechanisms comprissection, of the float and compression chamber, ing delicate parts which easily lost their adjustshowing the float at its lower limit. y ment, and had intermittently meshing gear trains Figure 6 is a fragmentary side elevational view, 10 which did not always function properly, or caused partly in Section 0n line 5-5 0I Figure 7. 0f a errors. modification of my pressure compensator.

The primary object of my invention is to pro- Figure '7 iS a fragmentary SeCtiOn 0n the line vide a device in which these defects are overcome. 1-1 of Figure 6. Another object of my invention is to provide Figure 8 is a fragmentary section on the line 15 a pressure compensator which can be readily and 8-8 of Figure '1. simply adjusted under operating conditions. Fig. 9 is a fragmentary pian, Partly in SeCtiOn. Still a further object of my invention is to proof a magnetically coupled oscillation transmission. vide a device which will automatically compensate Fig. 10 iS a fragmentary elevational Section 0f wir30 for pressure, readings of a gas or vapor now a metal bellows seal for a direct mechanical 20 meter operated under conditions of variable preslinkage. sure, and will register the now directly ln units Fis. 11 is an elevation, partly in section, oi' of weight or volume at a standard pressure. my invention With a mercury U-trap fOr Sealing Another object of my invention is to produce from the mains, with differential pressure in the a pressure compensator for gaseous or vapor ow U a minimum at Operating DreSSureS- 25 meters, which is simple, rugged, accurate and Fie. 12 is an elevation, partly in section. of a eiilcient. U-trap seal to permit expansion of gas in the With these and other objects in view which housing from Operating t0 ntmOSpherC pressure. will become apparent as the description proceeds, Fig. 13 is a fragmentary perspective view of a my invention consists essentially of a pressurereplaceable cam and roller cam follower. 30 tight housing adapted to be connected to a gas Fig. 14 iS a perspective view 0f 9 nipping lever or vapor transmitting system operating under mechanism. pressure, said housing containing a compressible Fig. 15 is a fragmentary perspective of a saddlegas confined within a closed chamber capable block mechanism. of being compressed by the system pressure trans- Fig. 16 is an elevation of a friction catch 35 mitted through a liquid medium, a float member mechanism. supported on the surface of said liquid externally c Referring to the drawings, I have shown in to said closed chamber, and two impulse inte- Figure 1 a housing i0 having an L extension i2 grating mechanisms, one adapted to increase a at. one side and a cylindrical register face i4 registered total by a constant quanntyror cach oc the front of housing lu. 'rnc housing m ls 40 impulse, and the other adapted to increase anprovided with a cover plate I6 secured to a flange other registered total, for each impulse, by a I8 by bolts 20. Pressure is transmitted to the dequantity which is varied according to a predetervice by means of the L I2 which is hollow and mined function of the simultaneous system prescommunicates with the interior of housing i0.

sure. Beneath the housing I0 is a cylindrical stud The invention, both as to details of construc- 22 having a threaded bore 24 communicating with tion and combination of parts, will best be underthe internal space of housing I0, a reduced porstood from the following description of a specic tion 28 having external threads and a shoulder embodiment which I illustrate as an example, 32. At the bottom of the housing rests a cylin- 50 when read in connection with the accompanying drical float chamber 34 which is provided with drawings, in which: a screw-threaded lower extension 36 adapted to Figure 1 is a side elevational view of my pres- 'be screwed into and project through the lower sure compensator.' opening 24 of the housing.

Figure 2 is a side elevational view, partly in A lock nut 38 screws on the projecting portion 55 of extension 36 and permits adiustment of the height of the chamber 34 within the housing.

' A screw-cap 40 is secured to the reduced portion 20 by means of threads 3l, and'a ring gasket 42 seated between the shoulder 32 and screw-cap 40 permits pressure sealing.

'Ihe float chamber 34 consists of an outer annular space 44, a concentric cylindrical space 40 occupying the lower inner portion oi' the chamber I4. and a larger concentric cylindrical space 40 occupying the upper inner portion of chamber 34 and communicating directly with space 40. Radial apertures l intercommunicate the lower ends of spaces 44 and 4I.

A gas l2. such as air. is placed in the float chamber and a. liquid 04, preferably mercury, is poured into the space 43. When pressure is applied to the surface of the mercury 54, it is transmitted to the gas 02, which is thereby compressed, the mercury thereupon rising in the space 44 and falling in the spaces 43 and 43. The spaces 44, 4B. and 4I are so proportioned that the mercury level in the inner spaces 4l and 40 is entirely within the space 40, over the range of pressure for which the device is designed to operate.

A float Il floats on the surface of the mercury, rises and falls in space 40. and is prevented from rising above that space by stops Il when the pressure is released and the mercury rises into moe 40. A stem 00 is attached to float 00 and is connected at the upper end by a pin and slot connection to a lever 32, which is nxed to a rotatable shaft 04. Said shaft 04 carries a cam II whose angular position is thus determined by noat Il.

An electromagnet 00 is mounted on a bracket Il which is pivotally mounted on a pin carried by a plate 'Il which is suspended from a disk 'I2 tting between the flange I0 and cover il, and separated therefrom by gaskets 'I4 to permit a pressure seal. The armature 'It ot electromagnet Il is independently pivoted on pin Il and carries a lever 00 which is linked at its outer end 04 to an oscillating lever 00 by a link 30. Lever 00 oscillates about an axle 00 and carries a series of pawls 02, which engage a ratchet wheel 34. also carried on axle 00, said pawls being proportioned so that they come into action alternately, so that the wheel 04 can be positively advanced fractional distances oi' the teeth. A bracket 3l secured to plate 'I0 carries a similar set of pawls to prevent reversal of rotation of the wheel 04 when lever I3 drops back to its lower position, after release of armature 10.

The electromagnet bracket 3l is provided with an extension arm 1| carrying a cam follower 02 which bears on cam '40. The angular position of electromagnet 0I about pin 10 is thus controlled through the cam Il by the position of float 33. The movement of lever l0 is limited at its lower position by a fixed stop 13 attached to plate 10, and at its upper position by the pole races of electromagnet Il, against which armature 10 comes to rest when said electromagnet is energised.

'I'he cam 00 is shaped so that the amount of movement of wheel I4 for each impulse of the electromagnet is controlled according to any desired relationship with the pressure.

A register 03 bearing dials III and a gear train |02 is secured to projecting lugs in the housing I0 by machine screws. A lug |04 and screw |03 are shown in Fig. 3. The main shaft |03 oi register l0 is separately secured to axle Il. A plate III, suspended from disk 12 similarly to plate 10. carries a bearing I|2 for axle 80, which is also journaled in plate 10. Cam shaft 04 is similarly journaled in plates 10 and |I0, extends through the rear plate |I4 of register 9| almost to the front register plate I i6, and carries on its end a vane I Il which is visible externally through the slot |20 in register plate IIB, the external edge of said slot being graduated so that the pressure may be read from the position of vane III.

A ratchet counter |22 is secured to plate I |0 so that its index is visible through an aperture |20 in plate ||4 and an aperture |20 in place I I0. 'I'his counter is operated by means of a lever arm |30 which bears a slot in which slides a finger |32 secured to oscillating lever 00, so that for each oscillation of lever 06 the counter is advanced a single digit. The operating throw of lever |30 necessary to operate counter |22 is sufilciently flexible to insure reliability of operation over a very wide range of movement of lever 00, as fixed by cam B0.

Electric impulses transmitted from some external source are conducted to electromagnet 00 by means of leads |34 and |38, lead |34 being shown grounded to the metal parts and lead being connected to a terminal in an electrically insulated pressure proof bushing |38.

The register face I4 is covered by a glass plate which is secured by an apertured cap |42 screw threaded to housing I0 and pressure sealed by means of ring gaskets |44 and |46.

The operation of the device. for example. when .connected to compensate a steam meter, is as follows:

Mercury is poured into the float chamber 34 to a fixed level near the top of space 43. The case is then filled with an electric insulating lubricating oil (not shown) and the cover bolted into place. Oil pressure with a test pressure gauge is then applied to the top opening of L I2 until some pressure within the normal operating range is reached. The reading of vane I I3 on scale |20 is noted, and, if not the same as on the test gauge, the cap 4l is removed, lock nut 33 loosened and screw 3l turned up or down until vane |I0 indicates the correct pressure, after which the lock nut is tightened and the cap replaced. The device is now ready to be attached to the steam line.`

An uncompensated volume or rate-of-ilow measuring steam meter (not illustrated) adapted to transmit electrical impulses for` predetermined nxed units of steam i'iow is attached to the mains to be metered and a pressure tap-off is taken for the pressure compensator and attached to L I2. The steam pressure acting on the device compresses the gas 52 in space 44, causing the oil in L I2 to be forced into housing I0 accompanied by water condensed from the steam. This water will gradually displace the oil up to the upper level |43 of the horizontal section of L I2. Oil will remain above this level and provide lubrication and protection from corrosion for all the mechanism with the exception of the float chamber and iloat. The float will assume a position trically connecting said meter to the housing and to the terminal in bushing |30, the electromagnet 68 Is energized, raising armature 16, lever 88. link 88,- and lever 86, and causing wheel 84 to advance a distance corresponding to the movement permitted between the fixed lower position of lever 86 and an upper position determined by the angular position of electromagnet 68 about pin 18, which in turn is controlled by the position of float 56 through stem 68, and cam 66. One of the pawls of bracket 8 6 then locks the wheel 94 so that the'return of lever 86 will not cause reverse rotation. This advance of wheel 94 is registered on the register dial train. Simultaneously, the finger |32 lifts the counter operating lever |38 and adds another digit to the counter index |24. The counter reading permits a check against the reading of the meter transmitting the electrical impulses.

This device thus not only registers compensated and uncompensated quantities, but also permits a direct reading of the steam pressure.

A modification of my invention is shown in Figures 6, 7, and 8, in which the cam 66 is relieved of the weightl of electromagnet 68 and is used instead as an upper stop to limit the movement of lever 88', so that the magnitude of said movement is determined by the position of the float through stem 68', lever 62', and the angular position of cam 66. Exceptfor the short interval during which the electromagnet 68 is energized and lever 88 therefore held tightly against cam 66', said cam is free to follow the movement of the float and iioat stem 68 without any restraining force such as` friction of the cam follower, magnet bracket, or the like.

In this modification it will be observed that electromagnet 68 is rigidly fastened to plate 18'. When electromagnet 58' is energized, it raises armature 'I6' and lever 88 until the latter strikes against cam 66 and is brought to a stop, this being the upper limit of the throw. The movement is transmitted to lever 86 and ratchet wheel 94' through the link 88 and pin 89, said pin connecting lever 86 and link 88 and being of sumcient length to project through curved slot 9| in plate 18. Pin 89, resting at the bottom of slot 9|, determines the lower limit of movement of lever 88 and associated mechanisms.

The modification of Figures 6 to 8, inclusive, is otherwise identical in construction and operation with the device of Figures 1 to 5, inclusive.

Although the illustrated embodiment of my invention has been shown as having a float chamber of cylindrical shape with the iioat at its center, for the purpose of maintaining substantial accuracy despite the device being considerably oif from a true vertical position, the chamber may have any desired shape or form. Instead of using mercury as the pressure transmitting in the float chamber, any other liquid which will not be diluted or added to by extraneous fiuids may be used..

In the embodiments hereinbefore described, mercury and oil Were used in the device, and for steam metering use the oil was displaced by water during use. With the use `of an iron, steel or stainless steel fioat, the Water would not cause a practical change in the pressure adjustment. If desired, however, the water can be initially added and the pressure test made under water pressure, or the device can be tested in the field under operating conditions.

If desired, the pressure may be applied to the device by way of a U trap containing suflicient mercury to compensate for the compression of lthe gas in space 44. In this case, also, the mercury can be adjusted so that the internal and external levels are approximately the same under operating pressures.

This construction is illustrated In Fig. 11. which shows a housing I8' to which pressure is transmitted by a U-trap extension I2', which contains a quantity of mercury 388 as a seal. The dimensions of extension I2' are such that the bottom of the U remains full of the liquid at atmospheric pressure and the interior level 384 does not spill over into the interior of housing I8 under conditions of maximum pressure. Mercury levels 382 and 384 are approximately equalized under operating pressures. At operating pressures the volume of gas in space 44 is small and relatively large pressure variations may occur without greatly unequalizing levels 382 and 384. The mercury seal construction has the advantage cf preventing dilution of the lubricating oil within the device.

Where a dry gas is used, or where condensed or suspended liquids may be trapped out, it is not necessary that the housing be filled with liquid,

yas hereinbefore described. This is particularly true where the gas is non-corrosive. In such case the mechanism bearings should be made selflubricating. Also, an auxiliary liquid seal can be provided of capacity large enough to permit the entire volume of gas within the housing to be compressed to operating pressures.

The construction of such a seal is illustrated in Fig. 12, in which pressure is transmitted from the mains to the meter housing I8" through a U-trap of large capacity comprising an inlet 3|6, an exterior arm 3I8 of large capacity, a similar interiorarm 3I2, and a liquid 3|4 to form the seal. At atmospheric pressure, arm 3I8 is nearly full of liquid and arm 3|2 nearly empty, with the level in arm 3 I 8 falling and that in arm 3I2 rising as the fiuid pressure is increased at inlet 3I6.

The relative proportions of the trap and meterA are such that the seal is maintained without spilling liquid into housing I8 under conditions of maximum pressure to which the device is to be subjected.

The device may be designed for practically any pressure range. The embodiments illustrated in .the drawings, however, are designed for a pressure range between 100 and 158 lbs. per sq. inch gage.

The device may be constructed with a stainless steel fioat to inhibit corrosion, although a float of any other material which will not amalgamate may be used, such as iron or aluminum. Similarly with respect to float stem 68. shape of the float is shown as spherical, but it may be of any shape, the purpose of the spherical downward surface being to reduce any error due to the possibility of the device being off true vertical. One bearing. for the fioat stem 68 is indicated at |48, Figure 2. A lower bearing being unnecessary in the construction shown as negligible error is introduced if the float 56 touches one side of the space 46.

In the illustration the cam follower 82 is shown as having a rubbing contact on the cam. In

order to eliminate friction and wear at this point,

the cam follower can be constructed as a roller, and further both cam and follower may be made easily replaceable.

Fig. 13 illustrates such construction. The extension arm II of the pivotally mounted electromagnet bracket is bifurcated at its outer end to form bearing members for a pin 8| carrying roller cam follower 82 which contacts the surface of a cam 63". Pin 3| is readily removable for purposes of replacement of both pin and roller. For ease in replacement, cam 66" is detachably secured to a shaft 64 by means of a key 323 in a keyway 322 in shaft 64 and a corresponding keyway in cam 66", a set screw 323 preventing longitudinal movement along said shaft.

In order to increase the accuracy of the pawl and ratchet wheel transmission, the teeth can be made much smaller and more numerous and the number of pawls can be increased. Furthermore, the transmission may be made by any similar means, for example, by a nipping lever, a saddle-block mechanism, or a friction catch mechanisxn for drive and lock. Fig. 14 illustratesthe nipping lever mechanism as applied in converting a reciprocating movement actuated electromagnetically or mechanically from the external source to cumulative rotation of a register-driving shaft. A loose ring 333 fits over a fiat rimmed wheel 332 which is fixed to a register-driving shaft 334. A nipping-lever 335 is pivoted at one end to an arm corresponding vto link 33 of Figs. 2, 3, and 4 and is pivoted on a pin 333 fixed to ring 333 and is concave on the surface 343 which is adapted to grip the wheel when a force is applied in the direction indicated by the arrow, forcing the ring tightly against the wheel on the opposite side and rotating the wheel in the indicated direction. When the lever 336 is moved in the reverse direction, the toe 342 strikes a shoulder 344 on ring 333 and slides the ring back over the wheel. A spring 343 tends to keep toe 342 in contact with the wheel so that the lost motion is negligible.

Fig. 15 shows a saddle-block mechanism adapted to perform the same function. Here a register driving wheel 353 has an annular rim 352 on the outside of which rests a saddle-block 354. A lever 353, pivoted at one end to an arm corresponding to link 33 of Figs. 2, 3, and 4 and pivoted to the saddle-block, projects inwardly past the rim and carries a pivotally mounted block 353 which fits the inner surface of the rim. When the lever is in such position that the pintles of blocks 354 and 353 are radially in line, the blocks slide freely along the rim. When lever 356 is moved in the direction of the arrow, the blocks grip rim 352 and further movement is communicated to wheel 353. When the lever is moved reversely, the grip is first loosened and then a stop 363 is encountered. after which further movement will slide the whole mechanism back over the wheel.

Fig. 16 illustrates a friction catch mechanism for converting the movement, in which a wheel 313 having a V-shaped groove is fixed to a reglater-driving shaft 312 on which a lever 314 oscillates freely. A friction catch 316 having a V- shaped edge 313 working in the groove of wheel 313 is pivoted to lever 314. Edge 313 is so shaped that movement of lever 314, which is pivoted at one end to an arm corresponding to link 33 of Figs. 2, 3, and 4, in the direction of the arrow will lock the catch in the groove, after which further movement will rotate shaft 312. Reversing the movement will release the catch and permit it to slide freely back over the wheel.

Instead of using a counter for indicating the transmitted impulses. these can be indicated on a dial gear train similar to the compensated registry, and can be made in identical units with those of the impulse transmitting meter so that their readings can be compared at a glance.

Although the float chamber adjustment has been illustrated as made with a central screw, it can be made in any convenient manner. The high adaptability of the device is illustrated by the fact that practically any correction factors may be introduced or compensated for by simply shaping the cam 56 appropriately. For example, any error due to a difference in level of mercury in chambers 44 and 46 is' easily compensated by the cam shape. It should also be noted that the cam follower is always substantially perpendicularly above the axis of the cam so that there is no opportunity for error due to misalignment. Again, this construction, particularly with a roller bearing cam follower, results in a minimum of resistance to movement of the float and cam.

Although the embodiments illustrated have been shown as being operated by electric impulses, this is not an essential feature. For example, an external magnet may be used to operate an oscillating member through a non-magnetic wall, or a mechanically operated lever can be directly introduced into the housing by way of a sylphon bellows which will permit the necessary movement and provide a pressure seal. Fig. 9 shows a construction using an oscillating external permanent magnet 253 attached to one end of a rocker arm 252 which pivots about a pintle 254 projecting Afrom the external face of a housing 256 adapted to have a difference in pressure on each side thereof. The other end of arm 252 is subjected to a force perpendicular to the plane of the drawings which causes the oscillations about pivot 254. Housing 256 is provided with a thin non-magnetic section 253 integral therewith and extending beyond the path traversed by magnet 253. An armature 263 is fixed to one end of an arm 262 freely pivoted on a shaft 264 whose axis is concentric with pintle 254. The other end of arm 262 is provided with a set of multiple pawls233 adapted to co-operate with a toothed wheel |33 fixed to shaft 264.. Due to magnetic linkage between armature 263 and .magnet 253, arm 262 will follow the oscillations of arm 252 and the angular displacement will be accumulated on wheel |93'. The movement of arm 262 is limited at one end of its travel by a fixed stop (not shown) and at the other by a cam operated by a pressure-responsive element (not illustrated) identical with that shown 'in Figs. 9 and 10.

Fig. 10 illustrates a mechanically operated rocker arm 213, which is mechanically oscillated about a pivot 214 in a yoke 216, by a force external to a housing 256' acting on a link 212 pivoted to one end of arm 213. Yoke 216 is secured to the outside of housing 253 on either side of an opening 216 in said housing. One end of a metal bellows 233 is sealed pressure tight to the periphery of opening 21| and the other end to arm 213 adjacent to pivot 214. This construction permits oscillation of arm 213 with relatively slight opposition as practically the only work done is in bending the bellows which is quite flexible. The inner end of arm 213 is con nected to oscillate a toothed wheel as illustrated in the other figures.

It will be obvious to those skilled in this art that the mechanisms shown in Figs. 9 and 10 may form the connection or a part of the connection between the armature 16 and the ratchet 64 which operates the register 133. In such a case, lever 252 oi' Fig. 9 and lever 213 of Fig. l0 will be operated by an armature corresponding to armature 1B of Fig. 2 which is in turn operated by an electro-magnet 68.

Although particular embodiments oi my invention have been described in considerable detail, such description is intended as illustrative rather than limiting, as it will be obvious to those skilledV in the art that various modifications ymay be made without departing from the spirit ofthe invention, and, therefore, the invention is not to be limited save as the scope of the prior art and the attached claims may require.

I claimz- 1. A pressure compensator comprising,a pressure-responsive element, a cam movable by said element in accordance with the pressure applied thereto, a register having a drive shaft, an electromagnet capable of being periodically 'magnetically energized by electric impulses received from an external source, an armature pivoted at one end and adapted to be draw-n towards said electromagnet when said electromagnet is ener--v gized, a fixed stop, a lever attached to said `arma'- ture, said lever bearing upon and having its movement limited by said cam 'when said armature is drawn vtoward saidelectromagnet and by said iixed 'stop on release thereof, a ratchet wheel fixed to the drive shaft of the register, an oscillating lever pivoted on said drive shaft, a link pivotally connecting said iirst-named lever and said oscillating lever, and a plurality of pawls on said oscillating lever, said pawls being adapted to engage the teeth of said wheel and being so proportioned that they come into action aiternately so that the wheel can be positively advanced fractional distances of the teeth.

2. In apressure compensator, a pressurere sponsive element, a cam shaft, a cam removably fixed to said cam shaft and rotatable according to a function of the pressure, a pivoted bracket,

'a roller cam follower iournaled in said bracket and cohoperating with said cam to control the .angular position of said bracket, an electromagh het fixed to said bracket, an armature adapted to be drawn to said electromagnet when energized, a fixed stop, a rotary member, an arm linked to said armature so that it is oscillated thereby on the axis of said member between the positions fixed by isaid stop and by said cam, a dial register coupled to and driven by said member, and means coioperating with said member and said arm whereby for each oscillation of the arm said member is unidirectionaily rotated' through the angle of oscillation oi said arm,

3. In a pressure compensator, a pressure-re-Y sponsive element, a cam mounted :or rotation in response to movements of said element, a nx'ed stop, a register, first means mounted for moveh ment between positions controlled by said cam and by said stop, second means for periodically operating said iirst means, third means coni necting said first means and said register so that said iirst means operates said register during movement of said rst means in one direc-g tion and said nrst means does not operate said register during movement of said first vmeans in the opposite direction, a housing enclosing said cam and said register and said third means. a liquid in said housing, a U-tra'p connected to 'said housing and adapted to receive and transmit pressure to said pressure-responsive element, and a second liquid in said vU--t'rap and 'adapted to maintain a seal to said housing even at the extreme pressures and to be at approximately equal heights in the arms of the U-tra'p at operating pressures. Y l

4. The combination of claim 3, in which the second liquid is heavier than the iirst mentioned liquid and is adapted not to spill over into the housing at maximum pressure. y

5. In a pressure compensator, a pressure-tight housing, a chamber within said housing, a compressible gas within said chamber', said charn-` ber communicating with the interior of said housing by at least fone aperture, a liquid in said housing extending into said chamber by way oi said aperture and confining and compressing said gas according to the pressure existing in said housing, a noot having a substantially spherical portion supported on the 'surface of said 'liquid within said housing externally to said chamber and a stem extending upward from said spherirlit cal portion, an integrating mechanism operated by periodic impulses and registering a total, said float being connected to said mechanism by said stem whereby for each impulse the registered total is increased by a quantity which is varied according to a predetermined function of the pressure within said housing; said chamber hsving a substantially cylindrical portion adjacent said spherical portion of said float and co-ope'ra ating therewith to form a guide for said float, and stops mounted at the upper end of the path of travel of said -dioat to linut the upward movement thereof. A i Y. s

6. vIn a pressure compensator, a pressure-tight housing having an opening therethrough, a hollow chamber detachabiy secured within said house ing and having an extension passing through said opening, locking means secured to said extension and adjusting said chamber relative to said housing, a compressible gas within said chamber, said chamber communicating with the interior of said housing .by at least one aperture, a liquid in said housing extending into said chamber by of said aperture and confronting and compressing said gas according to the pressure existing withi in said housing, fa float supported on the surface of said liquid within said housing externally to said chamber, :and an integrating mechanism operatedbyperlodlc impulses and registering s total, said float being operatively connected ito said mechanlsinby connections completely withi in said housing whereby for each impulse the rjeg 'istercd total is increased by a quantity which is varied according to s predetermined function of the pressure within said housingi WALTERV Ci WAGN l@ s 

